Method of spraying materials



R. M. STEPHENSON 36 837 METHOD OF SPRAYING MATERIALS Filed April 24, 1933 HIS A TT ORNE Y Patented Apr. W, 193% Application .tprill M, 1933, Serial No. 66?,522

2 tUlaims.

This application is a continuation in part of my copending application Serial No. 588,087, filed January 22, 1932, now Patent No. 1,979,649 issued Nov. 6, 1934.

My invention relates to the spraying of materials, and more particularly to a method of spraying high viscosity materials.

It is among the objects of my invention to provide a method of applying spray coats of high viscosity materials, such as the asphaltic compounds used on roofs.

Another object of my invention is to provide a method of incorporating a. fibrous material in the spray, so that the fibres are uniformly distributed throughout the applied coating.

Still another object of my invention is to provide a method of converting astrea'm of high viscosity material into a spray sheet having the uniform fan-shaped flow desired in the application of spray coatings.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of my invention. It is to be understood that I do not limit myself to this disclosure of species of my invention, as I may adopt variant embodiments thereof within the scope of the claims.

Referring to the drawing:

Figure 1 is a side elevational view showing apparatus for carrying out the method embodying my invention.

Figure 2 is a side view, partly in section and partly in elevation, showing the spray nozzle and its mounting.

Figure 3 is an elevational view showing another side of the nozzle; and

Figure 4 is an end view of the same.

In terms of broad inclusion, the method of spraying materials embodying my invention comprises forcing the material to flow in the form of a sheet, and then abruptly changing the flow so that the materi l movesin substantially the same direction bu in a sheet disposed at substantially right angles to the first sheet. In carrying out the method of my invention the material is forced under pressure through an elongated restricted orifice so that the material issues in the form of a sheet, and then directing the flow against the inner faces of a pair of opposed inclined planes having their converging edges spaced to provide an elongated restricted opening positioned crosswise of the orifice so that f the mixture issues from the opening in substantlally the same direction as the flow from the orifice but in a sheet disposed at substantially right angles to the first sheet.

The apparatus for carrying out the method embodying my invention includes a spray gun communicates with a source of air pressure. A

spray nozzle is provided and is also connected with the mixing chamber. This nozzle embodies the improvements of my invention and preferably comprises a tube having a tip portion restricted to provide an elongated orifice and having opposed lip portions extending outwardly and inwardly over the orifice; the forward edges of the lips being spaced to provide an elongated restricted opening positioned adjacentto and crosswise of the orifice.

In greater detail, and referring particularly to'Figure 1, the apparatus for spraying materials chosen to illustrate the method embodying my invention includes a spray gun 2 connected by means of the flexible hose 3 and t with the spray liquid supply tank t and with a flexible I hose ll communicating with a suitable source of air under pressure. The source of air pressure is not shown, but may conveniently be a compressor mounted on a truck. The air hose l is preferably connected directly to the hose it leading to the gun, and is connected to the tank t through the reducing valve t, so that the air in the tank may be maintained at a lower pressure than that supplied to the gun. A gauge 9 is preferably provided for indicating the pressure on the spray liquid in the tank.

The gun hose 3 communicates directly with the'liquid in the tank t, and is connected with the mixing chamber ll ofthe gun through a rigid pipe or duct it; a valve it being preferably included in this. connection for regulating the amount of spray liquid admitted to the mixing chamber. The air hose 4 also opens intothe chamber ii, and is connected therewith through a rigid pipe or duct M; a valve it also being preferably included in this connection for regulating the amount of compressed air admitted to the mixing chamber.

As shown in Figure l, the compressed air is directed into the'chamber l i so that it is injected at substantially right angles into the incoming stream of liquid. This arrangement results in a violent agitation of the liquid as it is driven hard towardthe head end. of the mixing chamher and into the spray nozzle ill. The nozzle is preferably connected with the chamber ll so that it extends in the direction of the resultant fiow of the mixed fluids.

The details of the nozzle and its mounting are best shown in Figures 2 to 4. The preferred form of nozzle comprises a tube l8, preferably cylindrical in shape, having a rectangularly-shaped recess it cut in its tipped end. The opposed lips 2i provided on the tube by the formation of the recess are flattened out to provide plane surfaces and are bent inwardly with their forward edges spaced to provide an elongated restricted opening 22. By this construction a pair of opposed inclined planes are provided with their converging edges spaced to form a restricted opening over the end of the tube. The side portions 23 ofthe tube adjacent the base edges 24 of the recess are flattened to provide an elongated restricted orifice 26 at the discharge end of the tube. It is to be noted that the elongated opening 22 defined by the forward edges of the lips 2| is positioned crosswise of the elongatedorifice 26. This is probably best shown in Figure 4.

Referring particularly to Figure 2, the tube 3 of the nozzle is threaded into a base plate 21 which seats over the open head end of the mixing chamber II and is held in place by a. threaded collar 28. This removable mounting gives ready access to the interior of the mixing chamber for purposes of cleaning, and also provides means for attaching nozzles having differently proportioned tip constructions. That is, for different types of liquid to be sprayed it is often desirable to use nozzles having diiferent sizes of restricted passages. For example, a spray liquid having a very high viscosity would ordinarily require a larger orifice 2B and opening 22 than would a A clear understanding of the method embodied in my invention will be gained in the following description of the operation of my apparatus. In practice the air hose 1 is preferably connected with a compressor adapted to develop an air pressure of from 100 to 125 pounds per square inch. Considering that the gun valves l3 and I6 are closed and that the material to be sprayed has been placed in the tank 6, the reducing valve 8 is preferably adjusted to maintain a pressure of from '75 to 100 pounds per square inch in the tank. The apparatus is now ready for applying the material.

A workman operates the gun by grasping the pipes l2 and M and the hose connections 3 and 4 so that the nozzle l1 extends to a point where the spray fluid is to be applied. In the drawing sections of the pipes I 2 and M are removed to shorten the view, but in the actual construction these pipes are preferably of considerable length, say about four feet, to enable an operator to work in the standing position. When spraying is to commence the operator opens the valves l3 and It. This action admits the liquid and compressed air into the mixing chamber H The intersecting streams of liquid and air result in a violent agitation within the mixing chamber and cause the fluid mixture to be driven hard toward the head end of the chamber. The condition of turbulence in the mixing chamber operates to thoroughly brealc up the material to be sprayed.

At the head end of the chamber the spray mixture passes into the tube l8 and travels rapidly toward the tip endof the nozzle. When the fluid reaches the tip it is forced through the restricted orifice 26 in the form of a sheet. This flow is im mediately altered however as the fiuid strikes the inner surfaces of the lips or bafiies 2i, and is abruptly changed into a flow moving in substantially the same direction but changed in form to a sheet disposed at substantially right angles to the sheet flow issuing from the orifice 26. The flow or spray issuing from the opening 22 is fanshaped and uniform and is well adapted for applying the material on the surface to be coated.

The spray gun of my invention is capable of handling a. material having a viscosity which is much higher than that usually handled by spray guns. This is due largely to the improved method in which the nozzle of my invention operates. I have found that the high viscosity fluids, such as'the fibrous matted asphaltic compounds used on roofs, may be sprayed without difiiculty by the use of my gun. The long asbestos fibres used in the roofing compounds are thoroughly broken up by the turbulent action in the mixing chamber and.- pass readily through the gun without clogging the nozzle.

These types of compounds have previously been mopped or squeegeed in place, but these methods of application were faulty in that they tended to roll up the fibres and concentrate them on certain areas of the surface being coated. By the use of a spray gun this is avoided, and the compounds are laid down with the fibres uniformly distributed throughout the coating. Furthermore, the spray gun sets the material down hard in the place where it is to stay, with the result that the material stays in place with the fibres interlaced through the bituminous material as the spraying proceeds. Not only is the resulting coating a better one, but it is applied much more rapidly than the older methods of mopping.

While I have described a particular type of material for use in the apparatus, it is tobe understood that any type of fluid may be applied with my spray gun. The particular value of my invention however lies in the fact that the improved action of my spray nozzle permits the gun to handle much heavier fiuid than has heretofore been possible.

I claim:

1. The method of applying a coating of asphaltic and fibrous materials so as to uniformly distribute the fibers throughout the coating, which comprises directing 'the asphalt containing the fibers in a fast moving stream, directing a stream of compressed air into said stream, forcing the resultant flow into a sheet, then abruptly chang ing the flow so that the mixture moves in the same direction but in a sheet disposed at substantially right angles to the first sheet, and directing the final stream on the surface to be coated.

2. The method of applying a coating of asphaltic and fibrous materials so as to uniformly distribute the fibers throughout the coating, which comprises subjecting the asphalt containing the fibers to pressure, directing the mixture in a stream, injecting compressed air into the stream, forcing the resultant flow into a sheet, then abruptly changing the fiow so that the mixture moves in the same direction but in a sheet disposed at substantially right angles to the first sheet, and then directing the final stream on the surface to be coated.

REUBEN M. STEPHENSON. 

